A method for controlling an internal combustion engine, a computer program, a computer readable medium, a control unit, an internal combustion engine, and a vehicle

ABSTRACT

The invention relates to a method to control an internal combustion engine. The internal combustion engine comprises a cylinder, an exhaust guide arranged to guide an exhaust flow from the cylinder through a turbine, and a bypass guide arranged to bypass a bypass flow from the cylinder past the turbine. The method comprises the step to determine a value of at least one engine operation parameter. The method is characterized by the step to determine a target value of an exhaust performance parameter depending on the determined engine operation parameter value. Further, the method comprises, depending on the determined target exhaust performance parameter value, the step to control the exhaust flow through the exhaust guide and the step to control the bypass flow through the bypass guide.

TECHNICAL FIELD

The invention relates to a method for controlling an internal combustionengine, a computer program, a computer readable medium, a control unit,an internal combustion engine, and a vehicle.

The invention can be applied in heavy-duty vehicles, such as trucks,buses and construction equipment. Although the invention will bedescribed with respect to a heavy-duty vehicle, the invention is notrestricted to this particular vehicle, but may also be used in othervehicles such as a car.

BACKGROUND

WO 2015/108472 A1 provides a method and a system arranged for control ofat least, one temperature for an exhaust treatment system in a vehicle.The system comprises a first determination unit, which is arranged forthe determination of the at least one temperature for the exhausttreatment system, and a second determination unit, which is 20 arrangedfor the determination of an order of priority for the use of brakes inthe vehicle. The order of priority is determined based on the at leastone temperature. However, further improvements are needed. Inparticular, in existing solutions considerable time and/or effort isneeded to heat up a cold exhaust aftertreatment system.

SUMMARY

An object of the invention is to decrease the emissions of internalcombustion engines in vehicles, especially at low ambient temperaturesand/or after a cold start and/or at a low engine load. Preferably, afurther object of the invention is to decrease the emissions of aninternal combustion engine already heated up at a low engine load.

According to a first aspect of the invention, the object is achieved bya method for controlling an internal combustion engine according toclaim 1. The internal combustion engine comprises a cylinder, an exhaustguide arranged to guide an exhaust flow from the cylinder through aturbine, and a bypass guide arranged to bypass a bypass flow from thecylinder past the turbine. The method comprises the step to determine avalue of at least one engine operation parameter. The method ischaracterized by the step to determine a target value of an exhaustperformance parameter depending on the determined engine operationparameter value. Further, the method comprises, depending on thedetermined target exhaust performance parameter value, the step tocontrol the exhaust flow through the exhaust guide and the step tocontrol the bypass flow through the bypass guide.

The method can be applied to control the internal combustion engine todecrease emissions of internal combustion engines in vehicles. Inparticular, the method can be applied to control the exhaust flow fromthe cylinder and the bypass flow from the cylinder to quickly heat up anexhaust aftertreatment system.

The internal combustion engine is provided to drive a vehicle. Such aninternal combustion engine may be provided as a diesel engine or agasoline engine. Preferably, the internal combustion engine is afour-stroke internal combustion engine. In a four-stroke internalcombustion engine a piston completes four strokes in one cycle. In thefirst stroke, the so called intake, an air flow is sucked into thecylinder. In the fourth stroke, known as exhaust, flue gas is pushed outof the cylinder providing a flue gas flow. The flue gas flow canpreferably be divided between the exhaust flow and the bypass flow. Theexhaust guide is provided downstream of the cylinder to guide theexhaust flow from the cylinder. Preferably, the internal combustionengine comprises one, two or more exhaust guides. Further, the bypassguide is provided downstream of the cylinder to guide the bypass flowfrom the cylinder. The second and third strokes are known as compressionand combustion. The internal combustion engine can comprise one or morecylinders.

The internal combustion engine is preferably provided with at least oneturbocharger. The turbocharger has a compressor and a turbine. Theturbine is driven with an exhaust flow from the cylinder. In turn, theturbine drives the compressor, preferably by means of a joint shaft. Thedriven compressor provides said compressed air to the cylinders forcombustion.

Preferably, the compressor is connected to the cylinder by means of anair guide. The air guide is arranged to guide the air flow from thecompressor to the cylinder. The turbine is connected to the cylinder bymeans of the exhaust guide. Further, downstream of the turbine, aturbine outlet guide may be provided that may guide the expanded exhaustflow from the turbine. The bypass guide may be arranged to bypass partof the flue gas flow as bypass flow past the turbine. For example, thebypass guide is arranged to guide the bypass flow from the exhaust guidepast the turbine. Preferably, the turbine outlet guide is arranged toguide the flue gas to an exhaust aftertreatment system. More preferably,the bypass guide is connected to the turbine outlet guide.

The internal combustion engine preferably is provided with an adjustableexhaust flow restriction element arranged downstream of the cylinder tocontrol the exhaust flow guided through the exhaust guide, inparticular, between the cylinder and the turbine. Further preferably,the internal combustion engine preferably is provided with an adjustablebypass flow restriction element arranged downstream of the cylinder tocontrol the bypass flow guided through the bypass guide, in particular,between the cylinder and the outlet guide or the exhaust aftertreatmentsystem. The respective adjustable flow restriction element may beprovided as an adjustable valve or throttle or flap. Preferably, therespective adjustable flow restriction element is continuously ordiscretely adjustable. In particular, the respective adjustable flowrestriction element may be adjustable between an open position providinga respective maximum flow and a closed position providing a respectiveminimum flow, e.g. 70 g per second. It is to be understood that therespective minimum flow may depend, for example, on the type of theinternal combustion engine or specification on an exhaust aftertreatmentsystem.

Preferably, the respective adjustable flow restriction element providesa respective adjustable flow area, which is, preferably, adjustablebetween different area dimensions. In particular, the respective flowarea is a cross-sectional area of a flow channel of the respectiveadjustable flow restriction element through which the respective flowpasses.

Preferably, the adjustable exhaust flow restriction element may becontrolled by means of an exhaust flow control signal value and theadjustable bypass flow restriction element may be controlled by means ofa bypass flow control signal value. The respective flow control signalmay preferably be a pneumatic and/or hydraulic and/or electromagneticcontrol signal. The pneumatic control signal and the hydraulic controlsignal may preferably be a pressure or flow rate signal. Theelectromagnetic control signal may preferably be a voltage or currentsignal. Preferably, the method may comprise the step of providing arespective flow control signal value to control the respective flow. Inparticular, the method may comprise the step of determining and/orgenerating and/or storing a respective flow control value.

The method for controlling such an internal combustion engine comprisesthe step of determining a value of at least one engine operationparameter.

An engine operation parameter preferably is a parameter that ischaracteristic for the operation of an internal combustion engine.Preferably, values for two or a plurality of three or more engineoperation parameters, in particular different engine operationparameters, are determined. In this way, a more detailed control can berealized. Determining the engine operation parameter value may includethe step of calculating and/or estimating and/or measuring the engineoperation parameter value. Thus, the internal combustion engine cancomprise at least one sensor to measure the engine operation parametervalue. To make use of the determined engine operation parameter valuefor controlling the internal combustion engine, the method can comprisethe step of storing a determined engine operation parameter value.

The target exhaust performance parameter value is determined dependingon the determined engine operation parameter value(s).

An exhaust performance parameter preferably is a parameter that ischaracteristic for the exhaust performance of an internal combustionengine. Preferably, target values for two or a plurality of three ormore exhaust performance parameters, in particular different exhaustperformance parameters, are determined. In this way, a more detailedcontrol can be realized. A target exhaust performance parameter valuecan be described as a desired value of an exhaust performance parameterto be achieved or reached or approached. The target exhaust performanceparameter value to be determined may change depending on the determinedengine operation parameter value. To make use of the determined targetexhaust performance parameter value for controlling the internalcombustion engine, the method can comprise the step of storing adetermined target exhaust performance parameter value.

The respective flows are controlled depending on a determined targetexhaust performance parameter value.

Controlling the exhaust flow or the bypass flow can comprise restrictingthe respective flow. The respective flow may be controlled such thatthey are zero. Further, controlling the respective flow can compriseincreasing or boosting the flow. Controlling the respective flowpreferably includes, for example continuously, adjusting, in particular,between a minimum and maximum respective flow. Controlling therespective flow through the respective guide may comprise controllingthe respective adjustable flow restriction element, respectively, sothat the exhaust flow area is suitably adjusted.

Further, controlling the respective flow may comprise increasing and/orreducing and/or maintaining an exhaust manifold pressure or bypass flowpressure, respectively. Further preferably, controlling the respectiveflow may comprise increasing and/or reducing and/or maintaining theexhaust flow or bypass flow with regards to its mass flow and/or volumeflow. Controlling a flow preferably comprises maintaining a previous orcurrent flow.

A determined target exhaust performance parameter value can be decodedinto a value of an exhaust flow control signal to control the exhaustflow and/or into a value of a bypass flow control signal to control thebypass flow. Thus, the method may comprise the step of decoding thedetermined target exhaust performance parameter value into a respectivevalue of a flow control signal, in particular, to control a respectiveadjustable flow restriction element. In particular, controlling therespective flow comprises the step of controlling the respectiveadjustable flow restriction element depending on the respective flowcontrol signal value. Preferably, the method may comprise the step ofstoring a respective decoded flow control signal value.

Preferably, the internal combustion engine, in particular the respectiveflows, are controlled open loop or closed loop. In particular, differentcontrol strategies may be adopted. For example, both the exhaust flowand the bypass flow, can be controlled open loop. In particular, boththe exhaust flow and the bypass flow, can be controlled closed loop.Further preferably, the exhaust flow can be controlled closed loop andthe bypass flow can be controlled open loop or vice versa. It can alsobe preferred to choose and/or switch between control strategies indifferent circumstances and/or situations.

All or some of the steps of the method described herein may preferablybe performed in the order described herein. Further preferably, all orsome of steps of the method described herein may be performed in anyorder. In particular, all or some of steps of the method describedherein may be performed in series or in parallel. For example, forcontrolling the internal combustion engine, some of the steps of themethod may be performed in series and other steps of the method may beperformed in parallel.

The method as described herein provides an advantageous solution todecrease the emissions of internal combustion engines in vehicles,especially at low ambient temperatures and/or after a cold start.Controlling both the exhaust flow and the bypass flow has the technicaleffect to increase the exhaust power of the internal combustion engine,which leads to a better performance of an exhaust aftertreatment systemand thus a reduction in emissions. In particular, at a low ambienttemperature value and/or a low engine coolant temperature value,controlling both the exhaust flow and the bypass flow has the technicaleffect to increase the exhaust power of the internal combustion engine,which leads to a better performance of an exhaust aftertreatment systemand thus a reduction in emissions.

Further preferably, the method has the advantage to make use of anincreased expansion ratio of the turbine, in particular when theadjustable exhaust flow restriction element is arranged between thecylinder and the turbine. Such an arrangement may increase the exhaustmass flow to an exhaust aftertreatment system. Nevertheless, by means ofthe adjustable bypass flow restriction element, the exhaust mass flowbeing provided to an exhaust aftertreatment system can be decreased.Thus, even if the exhaust flow is reduced by means of the adjustableexhaust flow restriction element, the exhaust aftertreatment system maybe provided with a higher exhaust power to quickly heat up the exhaustaftertreatment system due to a higher exhaust temperature value. In someload points, it may be preferred that the adjustable exhaust flowrestriction element is controlled to reduce the exhaust flow area and,yet, to increase the exhaust flow with regards to the mass flowproviding a higher exhaust power. In particular, the method provides theadvantage to choose between a high exhaust mass flow and a high exhausttemperature value. Preferably, depending on the determined currentengine operation parameter value(s) and/or the determined currentexhaust performance parameter value(s), the method provides theadvantage to choose between a high exhaust mass flow and a high exhausttemperature value.

According to one embodiment of the method described herein, the at leastone engine operation parameter is at least one of the following: anengine speed, and/or an engine load, and/or a coolant temperature,and/or an ambient temperature. Further, the exhaust performanceparameter is at least one of the following: an exhaust temperature,and/or an exhaust mass flow, and/or an exhaust manifold pressure, and/oran exhaust power.

Further preferably, an engine operation parameter can be a fuel flowand/or an engine oil temperature. Furthermore, an exhaust performanceparameter may be a turbine outlet temperature that is, for example, thetemperature inside of the turbine outlet guide or at or inside of anexhaust aftertreatment system.

Preferably, the engine speed is the rotational speed of an internalcombustion engine, in particular the rotational speed of its crankshaft.Determining the engine speed may comprise the steps of measuring theengine speed by means of a speed sensor. Further, the method maycomprise the step of storing a determined engine speed value.

Preferably, the engine load is the torque output of an internalcombustion engine. Determining the engine load may comprise determiningan air flow and a fuel flow provided for the combustion stroke, inparticular, calculating depending on the air flow and a fuel flowprovided for combustion. Further preferably, determining the engine loadmay comprise measuring the engine load by means of a torque sensor.Further preferably, the method may comprise the step of storing adetermined engine load value.

Preferably, the coolant temperature is the temperature of a coolantmedium cooling the internal combustion engine. The coolant medium may beair and/or a liquid such as water. In particular, the internalcombustion engine comprises an engine coolant system adapted to cool aninternal combustion engine with air and/or a liquid. Preferably, such anengine coolant system has a coolant temperature sensor to determine, inparticular, measure the coolant temperature. Further preferably,determining the coolant temperature may comprise estimating and/orcalculating the coolant temperature.

Preferably, the ambient temperature is a temperature periphery to theinternal combustion engine. In particular, the ambient temperature is atemperature outside of the internal combustion engine. Furtherpreferably, the ambient temperature is a temperature periphery to avehicle having the internal combustion engine. Further preferably, theambient temperature is determined at a plurality of locations.

Preferably, the exhaust temperature is the temperature of the exhaustflow. Preferably, the exhaust temperature is a temperature downstream ofthe cylinder of an internal combustion engine. In particular, theexhaust temperature can be a temperature between the cylinder and theturbine, further preferably, downstream of the turbine. For example, theexhaust temperature may be a temperature of the exhaust aftertreatmentsystem and/or the turbine outlet guide. Preferably, the temperatureupstream of the turbine is an exhaust temperature and the temperaturedownstream of the turbine is a turbine outlet temperature.

Preferably, the exhaust mass flow is the flue gas provided by thecylinders. In particular, the exhaust mass flow is the flow ofcombustion gas, preferably at least consisting of a fuel flow and an airflow. In particular, the exhaust mass flow is the mass of exhaust gasesemitted from the cylinders per time. Further preferably, the exhaustmass flow is the exhaust flow from the cylinder. In particular, theexhaust mass flow is the sum of the exhaust flow guided through theexhaust guide and the bypass flow guided through the bypass guide.Further preferably, the exhaust mass flow is determined downstream ofthe turbine, particularly, between the turbine and an exhaustaftertreatment system. Most preferably, the exhaust mass flow isdetermined at or inside of the turbine outlet guide.

Preferably, the exhaust manifold pressure is the pressure of the fluegas provided by the cylinders. Further preferably, the exhaust manifoldpressure is the pressure downstream of the cylinder, for example,between the cylinder and the turbine and/or between the turbine and theexhaust aftertreatment system, for example inside of the turbine outletguide. In particular, the exhaust manifold pressure is the pressure ofthe exhaust and/or bypass flow.

Preferably, the exhaust power is the power of an exhaust mass flow,particularly of the flue gas. Further preferably, the exhaust power isthe power of the exhaust mass flow. In particular, the exhaust power isa heat flow of the exhaust mass flow. Preferably, the exhaust power isapproximately a product of a specific thermal capacity, an exhaust massflow and an exhaust temperature value with regards to a referencetemperature value. In particular, the target exhaust power to bedetermined depends, for example, on the type of the internal combustionengine, such as its size, and/or a load point and/or an ambienttemperature value and/or an engine coolant temperature value.

Preferably, the specific thermal capacity is calculated in a test bedenvironment based upon conditions for the load point, for example anexhaust mass flow composition. For example, an ambient temperature valueof 25° C. may be a preferred reference temperature value. It is to beunderstood that the value of the specific thermal capacity may vary inan operation mode of the internal combustion engine. Preferably, thespecific thermal capacity may be a generic value in the operation modeof the internal combustion engine. Further preferably, the specificthermal capacity may be determined independent of a referencetemperature. Further preferably, an exhaust power value may bedetermined based upon an exhaust temperature value and/or an exhaustmass flow value or vice versa.

In one situation, for example at an ambient temperature value of forexample about 25° C. and after a cold start and/or a low engine load, anincreased exhaust power, for example about 35 kW, can be needed.Preferably, an adjustable exhaust flow restriction element is controlledto reduce the exhaust flow guided through an exhaust guide increasing acurrent exhaust manifold pressure value and a pumping work value.Preferably, an engine load value is kept constant by increasing injectedfuel to compensate for the higher pumping work. In some load points, itmay be preferred that the adjustable exhaust flow restriction element iscontrolled to reduce the exhaust flow area and, yet, to increase theexhaust flow with regards to the mass flow providing a higher exhaustpower. Thus, preferably, a fuel flow to a cylinder has to be increasedto maintain a constant brake torque. Further preferably, an increasingfuel flow increases a rotational speed of a turbo charger, increases anair flow, increases a compression of the air flow, and/or increases anexhaust mass flow. Thus, preferably, a cylinder of an internalcombustion engine may be provided with a higher air flow to fuel flowratio. In a particularly appropriate manner, such a higher air flow tofuel flow ratio may reduce an exhaust temperature value. Advantageously,the adjustable bypass flow restriction element may be controlled toreduce the air flow to achieve or approach a determined target exhaustmass flow value and/or a determined target exhaust temperature value.Preferably, the adjustable bypass flow restriction element may becontrolled to reduce the air flow by reducing the rotational speed ofthe turbo charger and, thus, to achieve or approach a determined targetexhaust mass flow value and/or a determined target exhaust temperaturevalue.

In another situation, for example, at an ambient temperature value ofapproximately about 25° C., and an already warmed up internal combustionengine and/or an already warmed up exhaust aftertreatment system,reduced emissions may be realized by controlling the internal combustionengine, in particular, by controlling the exhaust flow and the bypassflow differently. If the exhaust power has already reached or is aboutto reach or approach a determined target exhaust power value, e.g. 25kW, the internal combustion engine can mainly or solely be controlledvia the adjustable bypass flow restriction element. Preferably, as acurrent exhaust temperature value approaches or reaches a determinedtarget exhaust temperature value, the internal combustion engine maypreferably be controlled by means of the adjustable bypass flowrestriction element, wherein the adjustable exhaust flow restrictionelement is most preferably maintained in or set to a determined positionto provide a determined exhaust flow. In particular, the adjustableexhaust flow restriction element may be maintained in or set to adetermined position to provide an exhaust flow close to its maximum orto its maximum. Controlling the exhaust flow and the bypass flow and,thus, the air flow mainly by means of the adjustable bypass flowrestriction element is in particular suitable to decrease emissions of avehicle at a higher ambient temperature value and/or an already warmexhaust aftertreatment system.

The engine operation parameters and/or the exhaust performanceparameters are particularly suitable for depicting the condition of aninternal combustion engine with sufficient accuracy for controlling theinternal combustion engine, in particular the exhaust flow and/or thebypass flow. Further preferably, these engine operation parametersand/or exhaust performance parameters are particularly suitable forcontrolling a temperature of an exhaust aftertreatment system. Mostpreferably, the condition of an internal combustion engine is depictedbased on at least an engine speed value and an engine load value. Mostpreferably, the condition of an exhaust mass flow is depicted based onat least an exhaust temperature value and/or an exhaust mass flow value.These engine operation parameter values and/or exhaust performanceparameter values can be easily determined, which is why they areparticularly suitable for controlling an internal combustion engine, inparticular controlling an exhaust flow and/or a bypass flow.

According to one embodiment, the method further comprises the step ofdetermining a current exhaust performance parameter value. Depending ona deviation of the determined current exhaust performance parametervalue from the determined target exhaust performance parameter value,the exhaust flow through the exhaust guide is controlled. Furtherpreferably, depending on a deviation of the determined current exhaustperformance parameter value from the determined target exhaustperformance parameter value, the bypass flow through the bypass guide iscontrolled.

Preferably, current values for two or a plurality of three or moreexhaust performance parameters, in particular different exhaustperformance parameters, are determined. In this way, a more detailedcontrol can be realized. Preferably, a determined current exhaustperformance parameter value is a current value at a certain instance intime. In particular, a determined current exhaust performance parametervalue can represent an actual condition or state of the internalcombustion engine with regards to at least one exhaust performanceparameter.

A determined current exhaust performance parameter value may be supposedto reach or approach a determined target exhaust performance parametervalue. The determined current exhaust performance parameter value maychange depending on the engine operation parameter value, the exhaustflow and the bypass flow. The determined current exhaust performanceparameter value may be used to control the internal combustion engine.In particular, determining the current exhaust performance parametervalue may include the step of calculating and/or estimating and/ormeasuring the current exhaust performance parameter value. Inparticular, determining the current exhaust performance parameter valuemay comprise measuring and/or calculating and/or estimating an exhausttemperature value and/or an exhaust mass flow or an exhaust manifoldpressure value.

Preferably, the internal combustion engine comprises at least onecorresponding sensor to measure the respective current exhaustperformance parameter value(s). To make use of the determined currentexhaust performance parameter value for controlling the internalcombustion engine, the method can comprise the step of storing adetermined current exhaust performance parameter value(s). Determining adeviation value may comprise the steps of measuring and/or calculatingand/or estimating the deviation value.

Controlling the exhaust flow through the exhaust guide and/or the bypassflow through the bypass guide preferably depends on a deviation of adetermined current exhaust performance parameter value from a determinedtarget exhaust performance parameter value. Preferably, the method maycomprise the step of determining a deviation of a determined currentexhaust performance parameter value from a determined target exhaustperformance parameter value providing a determined deviation value.Depending on the determined deviation value an internal combustionengine, in particular an exhaust flow and/or bypass flow, can becontrolled, preferably controlled closed loop. Preferably, the methodmay comprise the step of storing the determined deviation value.

Preferably, the determined deviation value may be decoded into a valueof an exhaust flow control signal to control the exhaust flow and into abypass flow control signal value. Thus, the method may comprise the stepof decoding the determined deviation value into a respective flowcontrol signal value, in particular, to control the respectiveadjustable flow restriction element. Preferably, a respective decodedflow control signal value is decoded according to a control range oroperating range of a respective adjustable flow restriction element.

In particular, in case the determined deviation value is not equal tozero, the respective flow may be adjusted, preferably via at least onerespective adjustable flow restriction element. In particular, only theexhaust flow may be adjusted and the bypass flow is maintained or viceversa. In case an exhaust flow or bypass flow is maintained, therespective flow does not change, in the sense that no adjustment is madefor a specific deviation value. Preferably, if the determined deviationvalue is not equal to zero controlling the respective flow may comprisethe steps of increasing and/or decreasing and/or maintaining therespective flow. In particular, if the deviation value is zero,controlling the exhaust flow and/or the bypass flow may comprise thestep of maintaining the respective flow, in particular, the respectiveadjustable flow restriction element in a current or previous setting orposition.

Preferably, for controlling an internal combustion engine to reach orapproach a desired condition, the exhaust flow is controlled dependingon a determined deviation value and the bypass flow is controlleddepending on a determined target exhaust performance value. Furtherpreferably, for controlling an internal combustion engine to reach orapproach a desired condition, the exhaust flow is controlled dependingon a determined target exhaust performance value and the bypass flow iscontrolled depending on a determined deviation value. Most preferably,for controlling an internal combustion engine in order to reach orapproach a desired condition, both the exhaust flow and the bypass floware controlled depending on a determined deviation value.

The preferred embodiment of the method as described herein has theadvantage to increase the reaction speed of controlling, by controllingthe exhaust flow and/or the bypass flow depending on the deviation ofthe determined current exhaust performance parameter value from thedetermined target exhaust performance parameter value. Controlling thebypass flow between the cylinder and the turbine further has theadvantage to increase the accuracy and reliability of controlling theinternal combustion engine. This allows to quickly adapt the exhaustpower of the internal combustion engine, to quickly heat up the exhaustaftertreatment system and, thus, to reduce emissions in an advantageousway.

According to a further embodiment, the method further comprises the stepof determining an engine speed value and/or determining an engine loadvalue. Further, the method comprises the step of determining the targetexhaust performance parameter value depending on the determined enginespeed value and/or the determined engine load value.

Advantageously, this preferred embodiment makes use of engine operationparameters, namely engine speed and/or engine load. Since these engineoperation parameters are usually already determined, e.g. for anotherpurpose, the internal combustion engine can be controlled quickly andefficiently. This synergetic approach enables to control the internalcombustion engine in a cost-efficient way, however, still realizing afurther improved reduction of emissions. Further, these engine operationparameters are particularly advantageous since they can be used directlyto determine the condition of the internal combustion engine and, inparticular, the exhaust performance parameter. Particularly, the enginespeed and the engine load influence the combustion stroke and, thus, theexhaust mass flow. In particular, such engine operation parameters areadvantageously considered that influence the operating temperature ofthe exhaust aftertreatment system.

According to a further embodiment, the method further comprises the stepof determining a coolant temperature value and/or determining an ambienttemperature value and/or determining an exhaust temperature value.Further, the method comprises the step of choosing a value map fordetermining the target exhaust performance parameter value depending onthe determined coolant temperature value and/or the determined ambienttemperature value and/or the determined exhaust temperature value.Further preferably, the method further comprises the step of determiningthe target exhaust performance parameter value depending on thedetermined coolant temperature value and/or the determined ambienttemperature value and/or the determined exhaust temperature value.

Determining a respective temperature value may comprise measuring and/orcalculating and/or estimating a respective temperature value. Inparticular, the method may further comprise the step of storing thedetermined respective temperature value.

Preferably, determining a target exhaust performance parameter value maycomprise choosing and using a value map. Preferably, a value map is acharacteristics diagram, e.g. a two- or more-dimensional table,containing values of different parameters, in particular of at least oneengine operation parameter and at least one exhaust performanceparameter. Starting from the determined engine operation parametervalue(s), an associated target exhaust performance parameter value canbe identified in the diagram. Different value maps may be provided fordifferent ambient temperature values and/or different engine coolanttemperature values. In particular, such a value map may comprise targetexhaust performance parameter values associated to values of the engineoperation parameters engine speed and engine load. Preferably, startingfrom the determined engine speed value and/or determined engine loadvalue, an associated target exhaust performance parameter value can beidentified in the diagram. In particular, starting from the determinedengine speed value and/or determined engine load value, an associatedtarget exhaust temperature value and/or target exhaust mass flow valueand/or target exhaust manifold pressure value can be identified in thediagram. A value map or a set of value maps may be specified in a testbed.

A value map, in particular its characteristics diagram, may alsocomprise respective flow control signal values, in particular, inaddition to or instead of target exhaust performance parameter values.For example, starting from the determined engine operation parametervalue(s), an associated target exhaust performance parameter value canbe identified in the diagram, as well as associated respective flowcontrol signal values. Further preferably, the value map or a set ofvalue maps may be specified taking target exhaust performance parametervalues into consideration and directly associating respective flowcontrol signal values to the determined engine operation parametervalue(s). In this way, starting from the determined engine operationparameter value(s), the associated respective flow control signal valuescan be directly identified in the diagram.

Further preferably, determining a deviation of a determined currentexhaust performance parameter value from a determined target exhaustperformance parameter value may comprise using a value map. Preferably,such a value map may comprise exhaust performance parameter values andtarget exhaust performance parameter values, in particular, deviationvalues from the determined current exhaust performance parameter valuefrom the target exhaust performance parameter value. Further inparticular, such a value map comprises respective flow control signalvalues. Starting from a determined target exhaust performance parametervalue and a determined current exhaust performance parameter value adeviation value can be determined in the diagram. In particular,depending on the determined deviation value, associated exhaust flowcontrol signal values and/or bypass flow control signal values can beidentified in the diagram.

Different value maps may be provided for different ambient temperaturevalues and/or different engine coolant temperature values. Such a valuemap or a set of value maps may be specified in a test bed.

In particular, depending on the determined coolant temperature value avalue map for determining the target exhaust performance parameter valuemay be chosen. Further preferably, for determining the target exhaustperformance parameter value a value map may be chosen depending on thedetermined ambient temperature value. Further preferably, fordetermining the target exhaust performance parameter value a value mapmay be chosen depending on the determined exhaust temperature value.

Advantageously, this preferred embodiment allows to quickly and easilydetermining the desired target exhaust performance value, which allowscontrolling the internal combustion engine in such a manner that thetarget exhaust performance value is quickly reached or approached andthe emissions are quickly reduced, in particular after cold startsand/or at a low ambient temperature value. Further, particularly thecoolant temperature and/or the ambient temperature are engine operationparameters that are usually already determined, e.g. for anotherpurpose, thus, enabling to quickly and efficiently control the internalcombustion engine. In particular, they can easily be taken into accountto control the internal combustion engine. Further preferably, since thecontrol unit already provides a value map and/or a set of value maps,thus, already provides information about dependencies between differentparameters, it allows to easily and quickly access relevant values tocontrol the internal combustion engine efficiently.

According to a further embodiment, the method further comprises the stepof transforming a determined target exhaust power value to a targetexhaust temperature value. Further preferably, the method furthercomprises the step of transforming a determined target exhaust powervalue to a target exhaust mass flow value.

Further preferably the method may comprise the steps of determining atarget exhaust power value and transforming a determined target exhaustpower value to a target exhaust manifold pressure value.

Preferably, the step of transforming comprises the steps ofrecalculating and/or converting and/or translating and/or dividingand/or splitting and/or portioning. In particular, the step oftransforming comprises to transform a value into at least two values.Preferably, the determined exhaust power value is transformed into anexhaust temperature value and/or an exhaust mass flow value. Furtherpreferably, the determined exhaust power value is transformed into anexhaust manifold pressure value. Particularly, the exhaust temperaturevalue and/or the exhaust mass flow value and/or the exhaust manifoldpressure value are particularly suitable for use as parameters forcontrolling an internal combustion engine. Preferably, transforming thedesired target exhaust power value into a target exhaust temperaturevalue and/or a target exhaust mass flow value is based on an isobaricprocess. Further preferably, transforming the desired target exhaustpower value into a target exhaust temperature value and/or a targetexhaust mass flow value is based on an isochoric process. Transformingmay comprise measuring and/or calculating and/or estimating. Inparticular, the step transforming is based on the preferred dependencybetween an exhaust power that is approximately a product of a specificthermal capacity, an exhaust mass flow and an exhaust temperature valuewith regards to a reference temperature value as described above.

Preferably, the target exhaust power value is transformed into a targetexhaust temperature value if the exhaust mass flow value and the turbineoutlet temperature value are known. Further preferably, the targetexhaust power value is transformed into a target exhaust mass flow valueif the exhaust temperature value and the turbine outlet temperaturevalue are known.

For example, considering a certain type of an internal combustion enginethat is already heated up and an ambient temperature value of about 25°C., a target exhaust power of about 25 kW may be determined using avalue map based, for example, on a determined engine speed value of 1000rpm and a determined engine load value of 400 Nm. Such a determinedtarget exhaust power may further depend on the type of the internalcombustion engine and other parameters. The target exhaust power valuemay be transformed into a target exhaust mass flow and/or target exhausttemperature value. Transforming the determined 25 kW target exhaustpower value into a target exhaust mass flow and/or target exhausttemperature value may provide, for example, an exhaust mass flow ofabout 0.09 kg per second and/or an exhaust temperature value of about290° C.

For example, considering a certain type of an internal combustion engineafter a cold start and an ambient temperature value of about 25° C., atarget exhaust power of about 35 kW may be determined using a value mapbased, for example, on a determined engine speed value of 1000 rpm and adetermined engine load value of 400 Nm. Again, it is to be understoodthat such a determined target exhaust power may further depend on thetype of the internal combustion engine and other parameters. The targetexhaust power value may be transformed into a target exhaust mass flowand/or target exhaust temperature value. Transforming the determined 35kW target exhaust power value into a target exhaust mass flow and/ortarget exhaust temperature value may provide, for example, an exhaustmass flow of about 0.1 kg per second and/or an exhaust temperature valueof about 350° C.

Preferably, the target exhaust power value is determined based on avalue map having engine speed values and engine load values. Thedetermined target exhaust power value is transformed into a targetexhaust temperature value and a target exhaust mass flow value.Preferably, the target exhaust power value corresponds to a heat flowrequired by an exhaust aftertreatment system to quickly reduceemissions, in particular after a cold start and/or low ambienttemperatures.

Advantageously, this preferred embodiment allows transforming thedesired target exhaust power value into a target exhaust temperaturevalue and/or a target exhaust mass flow value. Controlling the internalcombustion engine by means of a target exhaust temperature value and/ora target exhaust mass flow value allows a very direct and precisecontrol of the exhaust flow in order to quickly heat up an exhaustaftertreatment system. Thus, the method of such a preferred embodimentfurther improves reduction of emissions of an internal combustion engineafter cold starts and/or at low ambient temperatures.

According to a further embodiment, the method further comprises the stepof determining a target exhaust temperature value and a target exhaustmanifold pressure value. Further, the method further comprises the stepof determining a current exhaust temperature value and a current exhaustmanifold pressure value. Depending on a deviation of the determinedcurrent exhaust manifold pressure value from the determined targetexhaust manifold pressure value the exhaust flow is controlled throughthe exhaust guide. Further, depending on a deviation of the determinedcurrent exhaust temperature value from the determined target exhausttemperature value the bypass flow is controlled through the bypassguide.

Preferably, the target exhaust manifold pressure and the target exhausttemperature are determined based on value maps depending on engine speedvalue and an engine load value both to be determined. Further, thisembodiment may comprise the step of choosing value maps for determiningthe target exhaust manifold pressure and the target exhaust temperaturedepending on a determined coolant temperature.

Determining a target and a current exhaust flow temperature value and atarget and a current exhaust manifold pressure value allows controllingan internal combustion engine in a very accurate manner. In particular,delay in controlling is reduced, which allows the internal combustionengine to quickly heat up an exhaust aftertreatment system. Thus,advantageously, such an embodiment of the method further reducesemissions of an internal combustion engine, in particular after coldstarts and/or at low ambient temperature values.

According to a further embodiment, the method further comprises the stepof controlling an air flow through an air guide. Preferably, the airflow is controlled depending on the determined target exhaustperformance parameter value and/or depending on the deviation of thedetermined current exhaust performance parameter value from thedetermined target exhaust performance parameter value.

Preferably, the method can be applied to control the internal combustionengine to decrease emissions of internal combustion engines in vehicles.In particular, the method can be applied to further preferably controlthe air flow to the cylinder to quickly heat up an exhaustaftertreatment system.

Preferably, the internal combustion engine can comprise an adjustableair flow restriction element arranged upstream of the cylinder tocontrol the air flow guided through the air guide. In particular, theadjustable air flow restriction element is arranged between thecompressor and the cylinder. Preferably, the adjustable air flowrestriction element comprises, mutatis mutandis, technical featuresand/or functionalities corresponding to some or all of the technicalfeatures and/or functionalities described above with respect to anadjustable exhaust flow restriction element and/or an adjustable bypassflow restriction element. In particular, as to the advantages andpreferred further details of the method step of controlling an air flow,reference is made to the corresponding advantages and preferred furtherdetails of the method step with respect to controlling the exhaust flowand/or bypass flow described above.

By controlling an exhaust flow, a bypass flow and an air flow, theinternal combustion engine, in particular, the operating temperature ofan exhaust aftertreatment system can be controlled even more preciselyand quickly. The method as described herein provides an advantageoussolution to decrease the emissions of internal combustion engines invehicles, especially at low ambient temperatures and/or after a coldstart and/or after low load, even further. The method has the advantage,by controlling the air flow, to increase the exhaust power of theinternal combustion engine, in particular to heat up the exhaustaftertreatment system more quickly. The present method providesadvantages in particular at a low ambient temperature and/or after acold start and/or after low load. Since the method for controlling aninternal combustion engine allows heating up an exhaust aftertreatmentsystem more quickly, emissions can be reduced in an advantageous way.

Furthermore, the method has the advantage to make use of an increasedexpansion ratio of the turbine, in particular when the adjustableexhaust flow restriction element is arranged between the cylinder andthe turbine. The increased expansion ratio enables to increasecompression of the air flow and, thus, to increase the air flow.Subsequently, even if the exhaust flow area is reduced by means of theadjustable exhaust flow restriction element the exhaust flow isincreased due to the increased air flow. Thus, the exhaustaftertreatment system is provided with a higher exhaust power.

According to a second aspect of the invention, the object is achieved bya computer program according to claim 9. The computer program comprisesprogram code means for performing the steps of the aspect andembodiments of the method described herein when said program is run on acomputer.

As to the advantages, preferred embodiments and details of the computerprogram, reference is made to the corresponding aspect and embodimentsof the method described above.

According to a third aspect of the invention, the object is achieved bya computer readable medium according to claim 10. The computer readablemedium carries a computer program comprising program code means forperforming the steps of the aspect and embodiments of the methoddescribed herein when said program product is run on a computer.

As to the advantages, preferred embodiments and details of the computerreadable medium, reference is made to the corresponding aspect andembodiments of the method described above.

According to a fourth aspect of the invention, the object is achieved bya control unit according to claim 11. The control unit for controllingan internal combustion engine is configured to perform the steps of theaspect and embodiments of the method described herein.

Preferably, the control unit is adapted to determine a target andcurrent exhaust performance parameter value, an engine operationparameter value and/or deviation of a 35 current exhaust performanceparameter value from a target exhaust performance parameter value. Inparticular, the control unit, is adapted to calculate and/or measureand/or estimate respective values. Preferably, the control unit isadapted to determine and/or generate and/or store a determined targetand current exhaust performance parameter value, a determined deviationvalue and/or a respective flow control signal value.

Preferably, the control unit may be connected to an adjustable exhaustflow restriction element and/or an adjustable bypass flow restrictionelement and/or an adjustable air flow restriction element by means of arespective flow signal line. Preferably, the control unit is adapted tocontrol the respective flow through the respective guide, in particularby being adapted to control the respective adjustable flow restrictionelement.

In particular, the control unit may be connected to respective sensors,in particular, a temperature sensor, a pressure sensor, a speed sensor,and/or a torque sensor. Preferably, the control unit is connected torespective sensors via respective signal lines. In particular, thecontrol unit may be adapted to determine and/or store a respectivesensor value.

As to the advantages, preferred embodiments and details of the controlunit, reference is made to the corresponding aspect and embodiments ofthe method described above.

According to a fifth aspect of the invention, the object is achieved byan internal combustion engine according to claim 12. Such an internalcombustion engine comprises a cylinder and a turbo charger having acompressor and a turbine driving the compressor. Further, an air guideis arranged to guide an air flow from the compressor to the cylinder.Further, an exhaust guide is arranged to guide an exhaust flow from thecylinder to the turbine. Between the cylinder and the turbine anadjustable exhaust flow restriction element is arranged to control theexhaust flow through the exhaust guide. In particular, the internalcombustion engine further comprises a bypass guide that is arranged tobypass a bypass flow past the turbine. Further, an adjustable bypassflow restriction element is arranged to control the bypass flow guidedthrough the bypass guide.

Preferably, between the compressor and the cylinder, an adjustable airflow restriction element is arranged to control the air flow guidedthrough the air guide.

According to one embodiment, an internal combustion engine comprises anexhaust flow temperature sensor arranged downstream of the cylinder.Further, the internal combustion engine can comprise an engine coolantsystem having a coolant temperature sensor and/or an ambient temperaturesensor arranged peripheral to the internal combustion engine.Preferably, the internal combustion engine may comprise an exhaust flowpressure sensor arranged downstream of the cylinder and/or an air flowpressure sensor arranged upstream of the cylinder. Preferably, theinternal combustion engine may comprise an engine coolant system havingsuch a coolant temperature sensor. In particular, the internalcombustion engine comprises a speed sensor adapted to determine anengine speed value. Further preferably, the internal combustion enginecomprises a torque sensor adapted to determine the engine load.

According to another embodiment, an internal combustion engine comprisesa control unit described herein. Further preferably, the internalcombustion engine described herein comprises an exhaust aftertreatmentsystem.

The invention also relates to a vehicle comprising an internalcombustion engine described herein. Preferably, the vehicle describedherein has an exhaust aftertreatment system.

As to the advantages, preferred embodiments and details of the internalcombustion engine and of the vehicle, reference is made to thecorresponding aspects and embodiments of the method described above.

Further advantages and advantageous features of the invention aredisclosed in the following description and in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, below follows a more detaileddescription of embodiments of the invention cited as examples.

In the drawings:

FIG. 1 is a side view of a vehicle in the form of a truck;

FIG. 2 is a schematic drawing of an example embodiment of an internalcombustion engine in the vehicle in FIG. 1;

FIG. 3 is a schematic drawing of a further example embodiment of aninternal combustion engine;

FIG. 4 is a schematic drawing of an example embodiment of an exhaustflow restriction element for an internal combustion engine as shown inFIG. 2-3;

FIG. 5 is a schematic block diagram depicting steps in an exampleembodiment of a method for controlling the internal combustion engine inthe vehicle in FIG. 1;

FIG. 6 is a schematic block diagram depicting steps in a further exampleembodiment of a method for controlling the internal combustion engine;

FIG. 7 is a schematic block diagram depicting steps in a further exampleembodiment of a method for controlling the internal combustion engine;

FIG. 8 is a schematic block diagram depicting steps in a further exampleembodiment of a method for controlling the internal combustion engine;

FIG. 9 is a schematic block diagram depicting steps in a further exampleembodiment of a method for controlling the internal combustion engine;

FIG. 10 is a schematic block diagram depicting steps in a furtherexample embodiment of a method for controlling the internal combustionengine;

FIGS. 11a-c are schematic depictions of different example embodiments ofa set of value maps;

FIG. 12 is a schematic block diagram depicting detailed example steps todetermine at least one engine operation parameter value;

FIG. 13 is a schematic block diagram depicting detailed example steps todetermine a target exhaust performance parameter value;

FIG. 14 is a schematic block diagram depicting detailed example steps todetermine a current exhaust performance parameter value; and

FIG. 15 is a schematic block diagram depicting detailed example steps todetermine a deviation of the determined current exhaust performanceparameter value from the determined target exhaust performance parametervalue.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

FIG. 1 shows a vehicle 10 in the form of truck or a tractor for asemitrailer. Further preferably, such a vehicle 10 can be a car, a busor a working machine. The vehicle 10 comprises an internal combustionengine 1, particularly a four-stroke internal combustion engine 1.Further preferably, not shown in FIG. 1, the vehicle 10 may comprise anexhaust aftertreatment system 8 that is connected with the internalcombustion engine 1.

FIGS. 2 and 3 show schematic drawings of possible example embodiments ofan internal combustion engine 1. However, the internal combustion engine1 claimed herein shall not be restricted or limited to the providedexample embodiments of the internal combustion engines. In particular,further embodiments of the internal combustion engine 1 may be acombination of shown example embodiments of the internal combustionengine 1 below and/or may not include certain features of the shownexample embodiments of the internal combustion engine.

FIG. 2 shows a basic embodiment of the internal combustion engine 1being provided in a vehicle such as shown in FIG. 1. Thereby, cylinders301, 302 are provided with an air flow via an air flow guide 901. Inparticular, the present embodiment has a turbocharger comprising acompressor 402 compressing the air flow and a turbine 401 driving thatcompressor 402. The turbine 401 and the compressor 402 are arranged on ajoint shaft to drive the compressor 402. Further preferably, not shown,the temperature of an air flow may be controlled by means of an enginecharge air cooler. An exhaust flow is provided from the cylinders 301,302 to the turbine 401 via exhaust guides 501, 502. In the depictedexample, two exhaust guides 501, 502 are shown. However, the exhaustflow provided from the cylinders 301, 302 can also be guided through asingle exhaust guide or through three or more exhaust guides. Theexhaust flow passes through the turbine 401 and expands. By expandingthe exhaust flow the turbine 401 is driven. The expanded exhaust flowmay be guided through a turbine outlet guide 801 that is arrangeddownstream of the turbine 401. The drive of the turbine 401 and thus ofthe compressor 402 can further preferably be controlled by a bypass flowthat is guided past the turbine 401. Preferably, the bypass flow isguided through a bypass guide 905 arranged to bypass the turbine. Inthis preferred example embodiment, the bypass guide is arrangeddownstream of the cylinder 301, 302 to connect exhaust guide 502 and aturbine outlet guide 801. For example, the turbine outlet guide 801 isarranged between the turbine 401 and an exhaust aftertreatment system 8.Preferably, the internal combustion engine comprises an adjustablebypass flow restriction element 904 and an adjustable exhaust flowrestriction element 601, 602 that are adapted to control the respectiveflows guided through the respective guides 501, 502, 905.

According to the embodiment in FIG. 2, the internal combustion engine 1comprises a control unit 21 that is adapted to control the adjustablebypass flow restriction element 904, and to control the adjustableexhaust flow restriction elements 601, 602 by means of signal lines6010, 6020, 9040. Particularly, the adjustable bypass flow restrictionelement 904 and the adjustable exhaust flow restriction elements 601,602 are continuously adjustable. In particular, the control unit 21 isadapted to provide a bypass flow control signal value to control theadjustable bypass flow restriction element 904 via signal line 9040.Further preferably, the control unit 21 is adapted to provide an exhaustflow control signal value to control the adjustable exhaust flowrestriction elements 601, 602 via signal lines 6010, 6020. Preferably,the respective control signals are electric and/or pneumatic signals.

Based on the example embodiment shown in FIG. 2 a further preferredexample embodiment shown in FIG. 3 depicts an internal combustion engine1 further comprising an adjustable air flow restriction element 903 tocontrol the air flow. The adjustable air flow restriction element 903 isadapted to increase, decrease and/or maintain the air flow guidedthrough the air guide 901. In particular, the adjustable air flowrestriction element 903 is arranged inside of or at the air guide 901.Particularly, the adjustable air flow restriction element 903 iscontinuously adjustable. In particular, the internal combustion engine 1has a further signal line 9030 that is arranged to connect the controlunit 21 with the adjustable air flow restriction element 903.

Preferably, the internal combustion engine 1 comprises an air flowpressure sensor 211 arranged at the air guide 901 upstream of thecylinders 301, 302. The air flow pressure sensor 211 is adapted todetermine a current air flow pressure value of the air flow guidedthrough the air guide 901. The internal combustion engine 1 alsocomprises an exhaust flow pressure sensor 214 arranged at the exhaustguides 501, 502 to determine an exhaust manifold pressure value of theexhaust flow guided through the exhaust guides 501, 502.

Further preferably, the internal combustion engine 1 comprises anexhaust flow temperature sensor 224 preferably arranged between theturbine 401 and an exhaust aftertreatment system 8. The exhaust flowtemperature sensor 224 is adapted to determine a current exhaust flowtemperature value of a flue gas guided through the respective guide 801.Further preferably, the internal combustion engine 1 comprises an enginecoolant system 701 having a coolant temperature sensor 714. Preferably,the coolant temperature sensor 714 is arranged to determine a currentcoolant temperature value of the internal combustion engine 1. Furtherpreferably, the internal combustion engine 1 comprises an ambienttemperature sensor 221. Preferably, the ambient temperature sensor 221is arranged to determine a current ambient temperature value.Preferably, the ambient temperature sensor 221 is arranged outside ofthe cylinders 301, 302. Most preferably, the ambient temperature sensoris thermally disconnected from the cylinders 301, 302 and arranged todetermine a current ambient temperature value of an ambient surroundinga vehicle 10.

According to the embodiment in FIG. 3, preferably, the internalcombustion engine 1 comprises a control unit 21 that is adapted tocontrol the air flow, particularly the adjustable air flow restrictionelement 903. In particular, the control unit 21 is adapted to provide anair flow control signal value to control the adjustable air flowrestriction element 903 via signal line 9030. Further preferably, thecontrol unit 21 is adapted to determine the current air flow pressurevalue via the air flow pressure sensor 211 and to determine the currentexhaust manifold pressure value via the exhaust flow pressure sensor214. Particularly, the internal combustion engine 1 has further signallines 2110, 2140 that are arranged to connect the control unit 21 withthe air flow pressure sensor 211 and the exhaust flow pressure sensor214. Preferably, an exhaust flow pressure sensor 214 may be associatedto an exhaust guide 501. Further preferably, an exhaust flow pressuresensor 214 may be associated to exhaust guides 501, 502. Furtherpreferably, the control unit 21 is adapted to determine the currentexhaust flow temperature value by an exhaust flow temperature sensor224. Further preferably, the control unit 21 is adapted to determine thecurrent coolant temperature value by a coolant temperature sensor 714.Further preferably, the control unit 21 is adapted to determine thecurrent ambient temperature value by an ambient temperature sensor 221.Particularly, the internal combustion engine 1 has signal lines 2110,2140, 2210, 2240, 7140 that are arranged to connect the control unit 21with the respective sensors 211, 214, 221, 224, 714. Preferably, therespective control signals and/or sensor signals are electric and/orpneumatic signals.

Preferably, the control unit 21 is adapted to control the air flowand/or the exhaust flow and/or the bypass flow depending on a determinedcurrent air flow pressure value and/or a determined current exhaustmanifold pressure value.

In particular, preferred embodiments of the internal combustion engine 1can comprise any combination of introduced adjustable restrictionelements 601, 602, 903, 904 and/or any combination of sensors 211, 214,221, 224, 714. Further preferably, the control unit 21 is adapted tocontrol the air flow and/or the exhaust flow and/or the bypass flow toquickly reach a determined target exhaust performance parameter value.

FIG. 4 shows an example embodiment of an adjustable exhaust flowrestriction element 601 of an internal combustion engine 1. Such anexample embodiment of the adjustable exhaust flow restriction element601 may be provided in one of the example embodiments of internalcombustion engines 1 introduced in FIGS. 2 to 3. The shown adjustableexhaust flow restriction element 601 is a butterfly valve with a flap604. The butterfly valve may comprise an exhaust flow restrictionactuation assembly 603 with a stepper motor, a brushless motor or apneumatic motor. Preferably, the exhaust flow restriction actuationassembly 603 is provided to adjust the adjustable exhaust flowrestriction element 601, i.e. to adjust an angular position of the flap604 around an axle 605 in order to adjust the exhaust flow area. Theflap 604 is non-symmetric, i.e. the extension of the flap is larger onone side of the axle 605 than on the other side. As a result, theadjustable exhaust flow restriction element 601 is arranged to assume,upon a fault in the exhaust flow restriction actuation assembly 603, aposition in which the adjustable exhaust flow restriction element 601does not restrict or block or limit the flow through the exhaust guide501. Preferably, the exhaust flow restriction actuation assembly 603 isadapted to be controlled by means of an exhaust flow control signalvalue. The adjustable air flow restriction element 903 and/or theadjustable bypass flow restriction element 904 may be designed, mutatismutandis, accordingly.

FIGS. 5 to 10 are schematic block diagrams depicting steps in preferredexample embodiments of a method for controlling an internal combustionengine 1, such as shown in FIGS. 2 and 3, in a vehicle 10, such as shownin FIG. 1. However, the method for controlling the internal combustionengine 1 claimed herein shall not be restricted or limited to theprovided example embodiments of the method. In particular, furtherembodiments of the method may be a combination of shown exampleembodiments of the method below and/or may not include certain steps ofthe shown example embodiments of the method.

In FIG. 5 is a schematic block diagram depicting steps in a preferredexample embodiment of a method for controlling the internal combustionengine 1. Particularly, this preferred embodiment of the methodcomprises four steps: determining a value of at least one engineoperation parameter S1, determining a target value of an exhaustperformance parameter depending on the determined engine operationparameter value S2, and controlling an bypass flow through the bypassguide 905 depending on the determined target exhaust performanceparameter value S3, and controlling the exhaust flow through an exhaustguide 501, 502 depending on the determined target exhaust performanceparameter value S4.

FIG. 12 is a schematic block diagram depicting detailed example steps todetermine at least one engine operation parameter value. In particular,determining the value of at least one engine operation parameter S1 maycomprise the steps of determining an engine speed value S1.1, and/ordetermining an engine load value S1.2, and/or determining a coolanttemperature value S1.3, and/or determining an ambient temperature valueS1.4. Further preferably, the at least one engine operation parameter isan air flow temperature and/or an air flow pressure. In particular,determining the engine speed value S1.1 comprises the step of measuringthe engine speed value by means of a rotational speed sensor beingprovided to measure the rotational speed of a crankshaft of thecylinders 301, 302. Further preferably, determining the engine loadvalue comprises the step of calculating the engine load value based on aprovided air flow and a provided fuel flow for a combustion stroke of acylinder 301, 302.

FIG. 13 is a schematic block diagram depicting detailed example steps todetermine at least one target exhaust performance parameter value. Inparticular, determining at least one target exhaust performanceparameter value S2 may comprise the steps of determining a targetexhaust temperature value S2.1 and/or determining a target exhaust massflow value S2.2 and/or determining a target exhaust manifold pressurevalue S2.3. Further preferably, the step of determining a target exhaustperformance parameter value may comprise the step of determining atarget exhaust power value S2.4. In particular, if a target exhaustpower value is determined S2.4, determining a target exhaust performanceparameter value further comprises the step of transforming a targetexhaust power value to a target exhaust temperature value and/or to atarget exhaust mass flow value S2.5. Further preferably, the exhaustperformance parameter is a temperature of an expanded exhaust flowdownstream of a turbine 401, particularly, guided through a turbineoutlet guide 801. Further preferably, an exhaust performance parameteris a temperature of an exhaust aftertreatment system 8. Most preferably,determining a target exhaust performance parameter value S2 comprisesdetermining target values for two or a plurality of three or moreexhaust performance parameters, in particular different exhaustperformance parameters.

Particularly, a determined target exhaust performance parameter value isa desired state of an internal combustion engine 1 that is supposed tobe reached or approached, particularly, to operate an exhaustaftertreatment system 8 in a desired state, preferably at a desiredoperating temperature. In particular, the determined target exhaustperformance parameter value is supposed to be reached or approached bythe step of controlling S3 the bypass flow through the bypass guide 905and/or by the step of controlling S4 the exhaust flow through theexhaust guides 501, 502. In particular, a controlled bypass flow and/orcontrolled exhaust flow may provide a reduced air flow to the cylinders301, 302 and/or provide a reduced flue gas flow from the cylinders 301,302. In particular, a controlled bypass flow and/or controlled exhaustflow may provide reduced respective flows. In particular, controllingthe respective flow may depend on certain circumstances and/orsituations, such as for certain sets of determined engine operationparameter values and/or determined target exhaust performance parametervalues.

Particularly, to control the bypass flow and/or the exhaust flow thedetermined target exhaust performance parameter values may be decodedinto a bypass flow control signal value and/or an exhaust flow controlsignal value. Preferably, the bypass flow control signal value and/orthe exhaust flow control signal value may be provided by means of acontrol unit 21 to control the adjustable bypass flow restrictionelement 904 and/or the adjustable exhaust flow restriction elements 601,602 to reach or approach the determined target exhaust performanceparameter value.

Preferably, in this preferred example embodiment of the method forcontrolling the internal combustion engine 1, the bypass flow and/or theexhaust flow may be controlled open loop depending on the determinedexhaust performance parameter value(s) and/or the determined engineoperation parameter value(s).

Thus, based on the example embodiment of a method for controlling theinternal combustion engine 1 shown in FIG. 5, the further exampleembodiment of the method for controlling an internal combustion engine1, as shown in FIG. 6, further comprises the step of choosing S5 a valuemap for determining the target exhaust performance parameter valuedepending on a determined coolant temperature value. In this preferredexample embodiment, the step of determining the target exhaustperformance parameter value depends on a determined engine speed valueS1.1, a determined engine load value S1.2 and a determined coolanttemperature value S1.3. Preferably, the set of value maps shown in FIG.11a may be value maps chosen in the example embodiment shown in FIG. 6.Thus, depending on a determined engine speed value S1.1, a determinedengine load value S1.2, and a determined coolant temperature value S1.3the target exhaust performance parameter value(s) are determined.

Preferably, target exhaust performance parameter values are determinedby means of value maps. FIG. 11a shows a schematic depiction of a set ofvalue maps providing target exhaust performance parameter valuesdepending on engine operation parameter values, in particular, dependingon engine load values, engine speed values and coolant temperaturevalues. The example embodiment shown in FIG. 11a discloses a set ofvalue maps, wherein different value maps are provided for differentcoolant temperature values.

In particular, decoding target exhaust performance parameter value(s)into respective flow control signal values may be based on a set ofvalue maps. An example embodiment of decoding a target exhaustperformance parameter value to an exhaust flow control signal value isschematically depicted in FIG. 11b . Further preferably, not shown, thedetermined target exhaust performance parameter value may be decodedinto a bypass flow control signal value and/or an air flow controlsignal value depending on a determined coolant temperature value.Preferably, such value maps are stored on a control unit 21. Mostpreferably, the dependency of target exhaust performance parameters andengine operation parameters is determined in a test bed environment.

Preferably, the set of value maps shown in FIG. 11a and the set of valuemaps shown in FIG. 11b may be integrated into one set of value maps.Preferably, each individual value map of a set of value maps can be inthe form of a two-dimensional table, as depicted in FIGS. 11 a, b, c,for example. Further preferably, each individual value map of a set ofvalue maps can be in the form of a three- or more-dimensional table.

FIGS. 7 to 9 show further preferred example embodiments of the methodfor controlling an internal combustion engine 1, wherein the internalcombustion engine 1 may be controlled depending on a deviation of adetermined current exhaust performance parameter value from a determinedtarget exhaust performance parameter value. Thus, the further preferredexample embodiments shown in FIGS. 7 to 9 may further comprise the stepsof determining a current exhaust performance parameter value S6 anddetermining a deviation of the current exhaust performance parametervalue from a determined target exhaust performance parameter value S7.

In particular, determining a current exhaust performance parameter valueS6 may comprise the steps of determining an exhaust temperature valueS6.1, determining an exhaust mass flow value S6.2 and/or determining anexhaust manifold pressure value

S6.3 as depicted in FIG. 14. In particular, the step of determining adeviation of the current exhaust performance parameter value from thetarget exhaust performance parameter value may S7 may comprise the stepsof determining a deviation of the current exhaust temperature value fromthe target exhaust temperature value S7.1, the step of determining adeviation of the current exhaust mass flow value from the target exhaustmass flow value S7.2, and the step of determining a deviation of thecurrent exhaust manifold pressure value from the target exhaust manifoldpressure value S7.3 as shown in FIG. 15.

In the preferred example embodiments shown in FIGS. 7 to 9 the bypassflow and/or the exhaust flow may be controlled depending on a deviationof the determined current exhaust performance parameter value from thedetermined target exhaust performance parameter value. In the exampleembodiment shown in FIG. 7 the internal combustion engine 1 iscontrolled, wherein the step of controlling the bypass flow S3 dependson a deviation of a determined current exhaust performance parametervalue from a determined target exhaust performance parameter value andthe step of controlling the exhaust flow depends on the determinedtarget exhaust performance parameter value S4. In particular, the bypassflow is controlled closed loop and the exhaust flow is controlled openloop. In the example embodiment of the method shown in FIG. 8 aninternal combustion engine 1 is controlled, wherein the bypass flow iscontrolled S3 depending on a determined target exhaust performanceparameter value and the exhaust flow is controlled S4 depending on adeviation of a determined current exhaust performance parameter valuefrom the determined target exhaust performance parameter. In particular,the bypass flow is controlled open loop and the exhaust flow iscontrolled closed loop. In the example embodiment of the method shown inFIG. 9 an internal combustion engine 1 is controlled, wherein the bypassflow and the exhaust flow are controlled S3, S4 depending on a deviationof a determined current exhaust performance parameter value from thedetermined target exhaust performance parameter. In particular, thebypass flow and the exhaust flow are controlled closed loop. Closed loopcontrol of an internal combustion engine 1 shall be explained based onthe example embodiment shown in FIG. 7. Preferably, in a closed loopcontrol, each step or a selection of steps may be executed in aniterative manner. For example, due to the controlled bypass flow, theexhaust performance of the internal combustion engine 1 will change.Preferably, the step of a current exhaust performance parameter valueS6, and the step determining a deviation of the current exhaustperformance parameter value from a determined target exhaust performanceparameter value S7 are iteratively applied to control the bypass flow asindicated in FIG. 7 with Y1. Further, after the bypass flow has beencontrolled S3 at least one engine operation parameter value, inparticular an engine speed value and/or an engine load value, maychange. Thus, it may be preferred to also iteratively determine thevalue of at least one engine operation parameter S1 and the at least onetarget exhaust performance parameter value S2, as indicated in FIG. 7with X1.

The steps for controlling the bypass flow closed loop as described forthe example embodiment shown in FIG. 7 may also analogously apply,mutatis mutandis, to the exhaust flow to be controlled depending on adetermined deviation value as shown in FIGS. 8 and 9 depicted by thedifferent possible closed loop control alternatives for the exhaust flowdepicted by the connections X2 between S4 and S1 and Y2 between S4 andS6.

Further preferably, an internal combustion engine 1 may be controlledaccording to an example embodiment shown in FIG. 9. In this preferredembodiments, the internal combustion engine 1 is further controlled bycontrolling the air flow S8. In particular, the step of controlling theair flow also depends on a deviation of a determined current exhaustperformance parameter value from a determined target exhaust performanceparameter value. Thus, the steps for controlling the bypass flow closedloop as described for the example embodiment shown in FIG. 7 may alsoanalogously apply to the air flow to be controlled. The differentpossible closed loop control alternatives are depicted by theconnections X3 between S8 and S1 and Y3 between S8 and S6.

Preferably, the example embodiments depicted in FIGS. 7 to 9 maycomprise the step of choosing a value map for determining the targetexhaust performance parameter value S5 according to FIG. 11a . Furtherpreferably, to control the exhaust flow, a set of value maps may bechosen according to FIG. 11c , wherein an exhaust flow control signalvalue may be identified depending on the deviation of a determinedcurrent exhaust performance parameter value from a determined targetexhaust performance parameter value. This procedure applies analogouslyfor controlling the air flow and/or the bypass flow. Preferably, the setof value maps shown in FIG. 11a and the set of value maps shown in FIG.11c may be integrated into one set of value maps. In particular, thedependency between respective flow control signal values and a deviationof a determined current exhaust performance parameter value from adetermined target exhaust performance parameter value and/or engineoperation parameter values is determined in a test bed environment.Further preferably, value maps or a set of a value map is determineddepending on a coolant temperature as shown in FIG. 11a-c and/or anambient temperature.

FIG. 10 shows a further preferred example embodiment of a method forcontrolling an internal combustion engine 1 closed loop, particularly,by controlling the bypass flow and the exhaust flow closed loop. Thispreferred example embodiment comprises the step of determining a valueof at least one engine operation parameter S1. Further preferably, acurrent exhaust temperature value may be determined S6.1 for determiningthe target exhaust performance parameter value S2. Particularly, thetarget exhaust performance parameter value shall be determined by meansof a value map. Thus, a corresponding value map shall be determined S5.In particular, the target exhaust performance parameter value shall bedetermined depending on the determined engine operation parameter andthe determined exhaust temperature value. Further preferably, in afurther step, the method comprises the step of determining a currentexhaust performance parameter value S6. Based on the determined currentexhaust performance parameter value and the determined target exhaustperformance parameter value a deviation shall be determined S7.Depending on the deviation of the determined current exhaust performanceparameter value from the determined target exhaust performance parametervalue the bypass flow and the exhaust flow may be controlled S3, S4.

Preferably, the method steps, in particular at least some or all of thesteps of the method described herein, may preferably be applied in thesequence described herein. Further preferably, some or all of the methodsteps may be applied in a sequence different from the sequence describedherein. Preferably, some or all of the method steps may be applied inparallel. Further preferably, the method steps, at least some or all ofthe method steps, may be applied in sequence.

It is to be understood that the present invention is not limited to theembodiments described above and illustrated in the drawings; rather, theskilled person will recognize that many changes and modifications may bemade within the scope of the appended claims.

1. A method for controlling an internal combustion engine comprising a cylinder, an exhaust guide arranged to guide an exhaust flow from the cylinder through a turbine of a turbo charger, wherein an adjustable exhaust flow restriction element is arranged downstream of the cylinder to control the exhaust flow guided through the exhaust guide, and a bypass guide arranged to bypass a bypass flow from the cylinder past the turbine, wherein an adjustable bypass flow restriction element is arranged downstream of the cylinder to control the bypass flow guided through the bypass guide, the method comprising the steps: determining a value of at least one engine operation parameter, wherein the at least one engine operation parameter is at least one of the following: an engine speed, and/or an engine load, and/or a coolant temperature, and/or an ambient temperature, characterized by determining a target value of an exhaust performance parameter depending on the determined engine operation parameter value, wherein the exhaust performance parameter is at least one of the following: an exhaust temperature, and/or an exhaust mass flow, and/or an exhaust manifold pressure, and/or an exhaust power and depending on the determined target exhaust performance parameter value, controlling the exhaust flow through the exhaust guide and controlling the bypass flow through the bypass guide.
 2. A method according to claim 1, comprising: determining a current exhaust performance parameter value, and controlling the exhaust flow through the exhaust guide depending on a deviation of the determined current exhaust performance parameter value from the determined target exhaust performance parameter value; and/or controlling the bypass flow through the bypass guide depending on a deviation of the determined current exhaust performance parameter value from the determined target exhaust performance parameter value.
 3. A method according to claim 1 comprising: determining an engine speed value and/or determining an engine load value, and determining the target exhaust performance parameter value depending on the determined engine speed value and/or the determined engine load value.
 4. A method according to claim 1 comprising: determining a coolant temperature value and/or determining an ambient temperature value and/or determining an exhaust temperature value, and choosing a value map for determining the target exhaust performance parameter value depending on the determined coolant temperature value and/or the determined ambient temperature value and/or the determined exhaust temperature value, and/or determining the target exhaust performance parameter value depending on the determined coolant temperature value and/or the determined ambient temperature value and/or the determined exhaust temperature value.
 5. A method according to claim 1 comprising: transforming a determined target exhaust power value to a target exhaust temperature value and/or to a target exhaust mass flow value.
 6. A method according to claim 1 comprising: determining a target exhaust temperature value, determining a target exhaust manifold pressure value, determining a current exhaust temperature value, determining a current exhaust manifold pressure value, controlling the exhaust flow through the exhaust guide depending on a deviation of the determined current exhaust manifold pressure value from the determined target exhaust manifold pressure value, and controlling the bypass flow through the bypass guide depending on a deviation of the determined current exhaust temperature value from the determined target exhaust temperature value.
 7. A method according to claim 1 comprising: controlling an air flow through an air flow guide, wherein the air guide is arranged to guide the air flow from the compressor to the cylinder, and wherein an adjustable air flow restriction element is arranged upstream of the cylinder to control the air flow guided through the air guide depending on the determined target exhaust performance parameter value; and/or depending on the deviation of the determined current exhaust performance parameter value from the determined target exhaust performance parameter value.
 8. A computer program comprising program code means for performing the steps of claim 1 when said program is run on a computer.
 9. A computer readable medium carrying a computer program comprising program code means for performing the steps of claim 1 when said program product is run on a computer.
 10. A control unit for controlling an internal combustion engine, wherein the control unit is configured to perform the steps of the method according to claim
 1. 11. An internal combustion engine comprising a cylinder, a turbo charger having a compressor and a turbine driving the compressor, an air guide arranged to guide an air flow from the compressor to the cylinder, an exhaust guide arranged to guide an exhaust flow from the cylinder to the turbine, an adjustable exhaust flow restriction element arranged between the cylinder and the turbine and arranged to control the exhaust flow through the exhaust guide, and a bypass guide arranged to bypass a bypass flow past the turbine, and an adjustable bypass flow restriction element arranged to control the bypass flow guided through the bypass guide characterized in that the internal combustion engine further comprises a control unit according to claim
 10. 12. An internal combustion engine according to claim 11, wherein the internal combustion engine comprises an exhaust flow temperature sensor arranged downstream of the cylinder, and/or an engine coolant system having a coolant temperature sensor, and/or an ambient temperature sensor arranged peripheral to the internal combustion engine, and/or an exhaust flow pressure sensor arranged downstream of the cylinder, and/or an air flow pressure sensor arranged upstream of the cylinder.
 13. A vehicle comprising an internal combustion engine according to claim
 11. 